Older adults spend over 8 hours per day sitting, more than any other age group. High sedentary time has now been associated with adverse health impacts (e.g. diabetes, cardiovascular disease related mortality) independent from physical activity. This suggests that research explicitly focusing on sedentary behavior is warranted. To further the field of sedentary behavior research among older adults with obesity, diabetes, and cardiovascular disease, three gaps will be addressed: 1) improving measures of sedentary time using advanced technology-based methods (due to limitations of self-reports and traditional accelerometer data processing techniques); 2) understanding relationships between sedentary time and cardio-metabolic biomarkers and health conditions; and, 3) developing technology-based interventions to reduce sedentary time. The iSTAND (Investigating Sedentary Time in Aging: New Directions using technology) Project aims to address these gaps using data from 3 rich sources (Successful Aging Evaluation [SAGE] Study, the Women's Health Initiative [WHI] Long Life Study, and a participant pool from a large integrated health care system). In the first research aim, objective measurement techniques for sedentary time (e.g. accelerometers, SenseCam, machine learning algorithms) are explored (Aim 1a), and machine learning algorithms for accelerometer data are applied to the WHI sample to examine relationships between sedentary time and health risk factors among older women (Aim 1b). In Aim 2, focus groups will be conducted to inform development of a technology-based sedentary time reduction program targeting older adults with obesity, diabetes, and/or cardiovascular disease. In a pilot intervention, the feasibility and acceptability of the intervention will be tested in 40 older aduls with obesity, diabetes, and/or cardiovascular disease from a large integrated health care system. The research plans dovetail with training plans for Dr. Rosenberg to obtain necessary skills and knowledge in 2 key areas where she has deficits: 1) wireless technologies to measure sedentary time more accurately, and, 2) application of wireless technologies to sedentary time reduction interventions among older adults. The project will be guided by a multidisciplinary team of expert mentors (bioinformatics, technology and measurement, geriatrics, statistics) and knowledge obtained through training experiences, coursework, and conferences. Support from this 4-year patient-oriented research career development award will position Dr. Rosenberg to lead an independent research program in using technology decrease sedentary time among older adults with chronic health conditions.